Investigating the Role of the Posterior Paraventricular Thalamic Nucleus in Habituation to Repeated Stress




Associate Professor of Anesthesiology and Critical Care

Project Summary

This summer I was fortunate enough to work in Dr. Seema Bhatnagar’s lab through the Penn Undergraduate Research Program. The Bhatnagar Lab aims to better understand individual differences in reactivity and vulnerability to stress through neurocircuitry in rat models. My project focused on examining how protein expression in the posterior paraventricular thalamic nucleus (pPVT) contributes to habituation in repeated stress. Earlier results demonstrated that lesioning the pPVT effectively prevented rats from habituating to stress. The lab wanted to further investigate the role of Arc protein expressed in the pPVT during habituation. Activity-regulated cytoskeleton-associated protein (Arc) is an early action gene that reduces excitatory synaptic number. I focused on how the expression of Arc protein changed in naïve young female rats that were repeatedly restrained over five days. The rats were placed in narrow containers which induced struggling behavior, an indicative sign of stress. As the treatment was repeated over a span of five days, the rats gradually decreased struggle behavior, showing habituation. In line with the rats’ behavior, the results showed that Arc expression rose on the first day, but significantly decreased by the fifth day. Thus, Arc expression presents a plausible correlation with habituation and a decrease in struggle behavior. Additional studies demonstrated that preventing expression of the Arc protein also prevented habituation.

My PURM experience has helped me develop a deeper appreciation and research skillset in the field of neuroscience. While procedures and ideas were easy to write on paper, physically handling rats taught me patience. In addition, the elaborate steps in the staining process for Arc protein provided easy ground for error. I used failed staining attempts as an opportunity to troubleshoot and refine staining techniques. From translating quantified protein numbers into conclusive data to asking my mentor and post doctorates about conceptual pathways, I also learned to think critically. This summer has expanded my interest in neuroscience research, and I am excited to continue working with my mentor this upcoming year.